What a clever take on the theme. I love the setup and it made me want to try all the different locations and scenarios for them. Really smart use of the limitation to make something incredibly fun that happened to revolve around the customization of a child's imagination.
I like that the gun and laser had unique attributes and weren't just sprite swaps. I love the attention to detail in things like the space level where I could jump way higher.
An excellent entry all around. One technical issue I noticed, nothing game breaking, just a little awkward. Is that the laser and the gun were really jittery when I was moving around. I guess that they're trying to move to a certain position relative to the player, but maybe your code order is a little out of place so it causes the constant jittering when moving. Not a big deal at all, just wasn't sure if you'd seen it.
Overall, I loved this entry. Great work.